Of course we can build a fusion reactor.=20
But there is no guarantee that this is possible. Of course =
controlled=20
fusion is possible - the sun does it all the time. But short of building =
a=20
star, it may be that plasma instabilities and all the other problems =
that=20
beset controlled fusion research will mean that fusion as a source of =
power=20
for everyday use just isn't viable.=20

I think this is perhaps too pessimistic. I'm sure most physicists =
working on Fusion really believe that it is possible; we are not relying =
on developing "warp drives" or other as yet unknown bits of physics to =
solve the technology problems. It is just that they will take far more =
time than we appear to have, if Glenn is correct about oil running out.

As it happens, I spoke to a plasma physicist who works on the JET =
experiment this morning after church. This is what happens next in the =
programme.

(1) The next big experiment is called ETA, and its purpose will be to =
demonstrate continuous generation of power by controlled nuclear fusion. =
However, there will be no attempt to convert this power into =
electricity. The purpose of the experiment is largely to determine the =
correct plasma parameters for a fusion reactor. The plasma =
instabilities are not an insurmountable problem, but one does need to =
build very large experiments costing billions, in order to get them =
right. At present, several sites in Europe, Japan and Canada are being =
considered and assessed for feasibility for building the experiment. =
Countries involved are Russia, Europe, Japan, Canada. Not America at =
present. Once the site is agreed on, it will take 12 years to build the =
experiment and get plasmas into it, and a further 12 for the =
experimental programme.

(2) The reusults from ETA are then supposed to feed into DEMO, a =
demonstration Fusion power station, which will supply electricity to the =
grid. This will also take 12 years to build and 12 to run. By which =
time the feasibility will have been established.

Hence the current estimate for when we get fusion in practice is 2050. =
I asked about Glenn's suggested 20 year time span. The response was as =
I expected; no-one working in Fusion research would consider 20 years =
as anything other than a "pipe-dream" (his words). Throwing extra =
money at it might reduce the timescales somewhat, but would never reduce =
it by anything like a half.

I also asked about the other technology problems that had to be solved. =
He was of the opinion that the Tritium breeding was not the most =
difficult problem (though still hard). There will be a lithium blanket =
in the ETA experiment. In his opinion the hardest problem was the =
design of the materials for the vacuum vessel. (To withstand corrosion, =
radiation, etc).

I can add here that I started my career at the UKAEA Culham labs =
particularly because I believed that Fusion was the future solution to =
our energy needs. That was in 1981. The very day I joined, the =
Conservative government axed the large experiment I was recruited to =
work on (RFX), which eventually got built on a reduced scale in Italy. =
The government continued its destructive course by turning the UKAEA =
into a Trading Fund, where we were obliged to make money by exploiting =
some of the technology that had been developed in the fusion programme. =
For example, much laser technology had been developed for plasma =
diagnostics (measuring the plasma temperature by Thompson scattering). =
The laser expertise we had developed was then diverted into more =
immediately lucrative projects, such as developing a machine for cutting =
a pattern in the security thread for the 50 pound note. That's what =
governments do to long term programmes that won't get them any votes =
when they come to get re-elected. Needless to say this is all pretty =
depressing, but it has to be said that the naive idealism with which I =
started my career has been replaced by a more realistic, if less hopeful =
attitude.

So it would appear to me that if its true that we're all going back to =
the middle ages if we don't get Fusion power stations being churned out =
by the dozen in 20 years, then that is precisely what will happen, and =
we'd better get used to the idea.